Background
- Prior epidemiological studies demonstrated that the p.D85N-KCNE1 common variant reduces repolarization reserve and predisposes to drug-induced QT prolongation/torsades de pointes. We sought to develop a cellular model for drug-induced long QT syndrome (DI-LQTS) using a patient-specific induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM).
Methods
- p.D85N-KCNE1 iPSCs were generated from a 23-year-old female with an exaggerated QTc response to metoclopramide (ΔQTc of 160 ms). CRISPR/Cas9 technology was used to generate "gene-corrected" isogenic iPSCs. Field potential duration (FPD) and action potential duration (APD) were measured from iPSC-CMs.
Results
- At baseline, p.D85N-KCNE1 iPSC-CMs displayed significantly longer FPD (281 ± 15 ms, n=13 vs. 223 ± 8.6 ms, n=14, p<0.01) and APD
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(579 ± 22 ms, n=24 vs. 465 ± 33 ms, n=26, p<0.01) than isogenic-control iPSC-CMs. Dofetilide at a concentration of 2nM increased significantly FPD (379 ± 20 ms, n=13, p<0.01) and APD
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(666 ± 11 ms, n=46, p<0.01) in p.D85N-KCNE1 iPSC-CMs, but not in isogenic-control. The effect of dofetilide on APD
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(616 ± 54 ms, n=7 vs. 526 ± 54 ms, n=10, p<0.05) was confirmed by Patch-clamp. Interestingly, treatment of p.D85N-KCNE1 iPSC-CMs with estrogen at a concentration of 1nM exaggerated further dofetilide-induced APD
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prolongation (696 ± 9 ms, n=81, p<0.01) and caused more early afterdepolarizations (EADs) (11.7%) compared to isogenic control (APD
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: 618 ± 8 ms, n=115 and EADs: 2.6%, p<0.05)
Conclusions
- This iPSC-CM study provides further evidence that the p.D85N-KCNE1 common variant in combination with environmental factors such as QT prolonging drugs and female sex is pro-arrhythmic.
Isogenic human pluripotent stem cell pairs reveal the role of a KCNH2 mutation in long-QT syndrome
